Silicon carbide (SiC) has a high breakdown voltage and is expected as a next-generation material of power semiconductors. Moreover, silicon carbide transmits visible light, and the coefficient of thermal expansion and lattice constant thereof are close to those of gallium nitride (GaN). Accordingly, silicon carbide is widely used for substrates of GaN-based LEDs and is a promising material used for semiconductor devices and ceramics.
Such silicon carbide has excellent heat resistance and is expected to be applied to mechanical parts used at high temperature and the like. Those applications often require high mechanical strength, and silicon carbide is infiltrated into a preform made of ceramic fibers to be provided as a heat-resistant composite material with the toughness increased.
The aforementioned heat-resistant composite materials are manufactured by depositing silicon carbide on the microstructure of preforms accommodated in a reactor often by chemical vapor deposition (CVD) or chemical vapor infiltration (CVI). There are two options for the material gas of silicon carbide including: a mixture of silane (SiH4) gas and hydrocarbon gas; and an organic silicon compound such as methyl trichlorosilane (CH3SiCl3: MTS).